The word "unsummerlike" refers to anything that is not reminiscent of or suitable for the summer season. There are several antonyms of this word that represent the opposite of unsummerlike. These antonyms include "sunny," "warm," "bright," "hot," and "summery." Each of these words represents the essence of summer, including its warmth, sunshine, and bright colors. Other antonyms of unsummerlike may include "winter," "cold," "snowy," and "frigid," which are opposite to the warm, sunny nature of summer. In summary, the antonyms of unsummerlike denote the characteristics that are typical of summer, including warmth, sunshine, and high temperatures.